Prosthesis for below-knee amputees



April 24, 1962 M. M. BAlR 3,030,634

PROSTHESIS FOR BELOW-KNEE AMPUTEES Filed Oct. 30, 1958 3 Sheets-Sheet 1FIG.I

INVENTOR.

MILFORD M. BAIR ATTORNEY.

April 1962 M. M. BAIR 3,030,634

PROSTI- XESIS FOR BELOW-KNEE AMPUTEES Filed Oct. 30, 1958 3 Sheets-Sheet2 ll lllllll INVENTOR. MILFORD M. BAIR FIG. 5 y g ATTORNEY April 24,1962 t M M. BAIR 3,030,634

PROSTHESIS FOR BELOW-KNEE AMPUTEES Filed Oct. so, 1958 s Sheets-Sheet sAT TOR NEY.

Unite States The present invention relates to prosthesis for belowkneeamputees.

The desideratum of the present invention is to enable below-kneeamputees to flex their knees from a substantially straight-out positionto a maximum bent position without the painful cutting effects resultingfrom the movement of the amputated tibia relative to the boot support inwhich the same is accommodated or received; to enable below-kneeamputees to do all those things that they formerly did with their normallimbs; to sit with their legs bent under them, to squat on their knees,dangle their legs ed the end of a pier or dock, to take high stepswithout abnormal manipulations and, in particular, to do the same thingsin the same way that normal people can.

Although below-knee amputees have the ability to operate and manipulatetheir knees, they cannot do so at the present time without unsightlyprosthetic devices that bulge from the sides of the knees and severelymangle and subsequently tear the clothing that they wear. The presentinvention has as its object the provision of an artificial knee jointwhich permits the wearer to operate his knee without creating an unusualor unsightly appearance along the sides of his trouser, to provide aknee joint in which the working parts are so encased and covered thatclothing coming in contact therewith will not be gripped thereby as tobe torn or mangled.

It is another object of the invention to provide a knee joint thatpermits the movement of the human knee without obstruction but which isadapted to retract or to be displaced so as not to interfere with thewearers knee.

It is another object of the invention to provide a prosthesis forbelow-knee amputees that includes a boot having a unique retractablerear portion for the receipt of the amputated tibia such that the bootwill retain a constant engagement with a predetermined aft portion ofthe wearers knees despite the movements of the boot relative to thewearers amputated leg during manipulations of the knee, thus assistingand providing the wearer with a full measure of contact about theamputated leg such that full manipulations of the knee may be made.

Another object of the invention is to provide a prosthetic devicecomprising an artificial knee joint and stump receiving boot that willcooperate in a unique manner as to permit the aft portion of the boot tovary in height in accordance with the flexing of the knee to remain inconstant engagement with a predetermined aft portion of the wearersknee.

Other and further objects of my invention reside in the structures andarrangements hereinafter more fully described with reference to theaccompanying drawings in which:

FIG. 1 is a perspective view of a portion of the boot and knee hingeconstructed according to the teaching of the invention,

FIG. 2 is a side view of the knee hinge and a diagrammatic showing ofits cooperation with the boot,

FIG. 3 is a section taken along lines 33 of FIG. 2,

FIG. 4 is a view similar to FIG. 2 wherein the wearers knee is slightlybent,

FIG. 5 is a view similar to FIG. 2 showing the wearers knee bent toapproach a sitting position,

FIG. 6 shows the knee joint bent into substantially a perpendicularposition,

FIG. 7 shows the knee so that the femur and tibia are ice angularlymoved with respect to each other such that the angle therebetween isless than FIG. 8 is a partial view of the aft side of the boot,

FIG. 9 is a side View of the slide shown in FIG. 8,

FIG. 10 is a plan view of the slide actuator link and mechanism, and

FIG. 11 is an end view of FIG. 10.

Referring now to the drawings, the prosthetic device shown in FIG. 1 isgenerally identified by the numeral 20. For ease of explanation and toaid in the description of the device 20, the same is arbitrarily dividedinto two parts. The first, an anatomical knee joint or hinge isgenerally identified by the numeral 22. The second comprising a boot, isgenerally termed a posture adapter and is identified by the numeral 24.

The knee joint 22 comprises at its ends, a pair of relatively movablelevers 26 and 2S. Lever 26 is identified as the upper lever while lever28 is identified as the lower lever. The upper lever 26 is adapted to besecured in such manner as to be fixed with respect to the femur of thewearer of the device 20 for coordinated movements therewith. The lowerlever 28 is adapted to be secured so as to be fixed for relative andcoordinated movement with the amputated tibia of the wearer. Hence, themovementof the lower lever 28 follows that of the amputated tibia whilethe upper lever 26 follows the movements of the femur. In practice andas more clearly seen in FIG. I, the lower lever 28 is fixed to the bootstructure 24 in a manner to be described. At this time however, it willbe recognized that by securing the lower lever 28 to the boot structure24, it is caused to move with the amputated tibia that is adapted to bereceived therein.

The upper lever 26 is mounted at 30 in an upper lever housing 32 forpivoted movement therein. An upper link means or structure 34 and 34aare also pivotedly mounted within the upper lever housing at 36 and 38.Attention is directed to FIG. 3 wherein it is to be noted that the leverand link combination of structure thus described defines a planarrelationship between the side walls of the upper lever housing 32. Thisprovides for a very compact narrow engagement of structure that iscarried forth throughout the remainder of the knee joint to bedescribed.

The upper link means 34 and 34a are bulbous in shape and are permittedrelative movement but engaging cooperation with the lower widenedportion of the upper level 26. This engaging cooperation may be in theform of cooperating gear teeth 40 as shown in FIGS. 1 and 10, although,here again, it will be understood that other convenient engaging meansmay be employed. In prac tice, however, it has been found that the useof the engaging gear teeth provides a simple yet efficient mechanismwhereby the relative movement between the lever and link structures maybe predeterminately limited.

The lower ends of the upper link means 34 are pivotally mounted at 42and 44 respectively, in a fulcrum housing 46. The pivoted lower bulbousends of the link means 34 and 34a cooperatively engage with upperbulbous portions of a lower link structure or means 48 and 50respectively that are also pivotally mounted within the confines of thefulcrum housing 46 at 52 and 54. The lower bulbous ends of the lowerlink means 48 and 50 are pivotally mounted at 56 and 58 in a lower leverhousing 60. Pivotally mounted at 62 in the lower lever housing 60 forengagement with the lower bulbous portions of the link means 48 and 50,is the lower lever 28.

As previously noted, the planar arrangement of the upper and lowerlevers 26 and 28 and the respective upper and lower link structures 34,34a, 48 and 50, is shown in FIG. 3. This provides for a narrow compactarrangement of structure. The bulbous ends of the upper lever 26 and thelower lever 28 may be provided with engaging teeth 49 such as that shownin FIG. 1 or as shown in FIG. wherein there is an expanded view of oneof the lower link means 56. The cooperating upper and lower linkstructures engaging the upper and lower levers 26 and 28 respectivelyare bulbous in shape to accommodate the proper number of engaging gearteeth 40 for cooperative engagement with the gear teeth on the bulbousportions of both the upper and lower levers 26 and 28.

It will be noted from the drawings that the central connecting bodyportion of each of the link means 34, 34a, 48 and 50, is bowed outwardlywith convex outer surfaces and concave inner facing surfaces. Theiroutwardly bowed connection portions permit their relative movement froma position as depicted in FIG. 2 wherein the upper and lower levermembers 26 and 28 are approximately or substantially in alignment to anextreme bent position as depicted in FIG. 7. Since it is well known thatthe human knee joint is not a perfect hinge, when in the standingposition, the femur and tibia are not in a straight line. Rather, theyare slightly angula-rly bent with respect to each other at an angle'morenearly approaching 178 about the aft portion of the leg. Progressivebending of the tibia and femur angularly relative to each other from thesubstantially straight position, results in a decrease of the angularseparation therebetween about the aft portion of the knee.

The present inventive hinge 22 is adapted to bend or flex with the humanknee without, however, creating an unsightly appearance along .the sidesof the knee by bulging the clothes outwardly during such bendingmovement, on gripping and tearing the clothes during such outwardbulging. It has often been a common complaint of arnputees that the kneehinge provided for them has so many exposed working parts that theseparts grip -the clothes and tear them, rendering a new set of trousersoldin appearance after only a short period of Wear. Also, in the attemptto make the artificial knee joint operate in the same manner as thehuman knee, there is created an unsightly bulge along adjacent sides ofthe knee. The instant unique knee joint 22 is intended to permit thehuman knee to operate in its normal manner and although it can bepositioned along the adjacent sides of the human knee, its uniquefeatures and design obviate the possibility of gripping and tearing ofclothes and also eliminates the unsightly bulges that are created alongthe sides of the wearers knee.

To accomplish this, the instant knee joint 22 functions to move thefulcrum housing 46 linearly toward and away from a theoretical pivot 64during the relative angular movements of the amputated tibia and femur.Thus, for example, the substantially straight line position of the upperand lower levers 26 and 28 as depicted in FIG. 2 has positionedtherebetween the fulcrum housing 46. As the upper and lower levers 26and 28 are moved angularly toward or away from each other in response tothe corresponding angular movements of the femur and amputated tibia,the fulcrum housing 46 is also causedto be displaced linearly eithertoward or away from the theoretical pivot point 64 defined between theangularly spaced upper and lower levers 26 and 28. This movement iswidened in subsequent FIGS. 4, 5, 6 and 7 wherein as the upper and lowerlevers 26 and 28 are moved angularly toward or away from each other, thefulcrum housing 46 is similarly linearly displaced toward or away fromthe theoretical pivot 64.

It is to be understood, and this will be recognized from viewing FIGS. 2to 7 inclusive, that the fulcrum housing 46 is displaced in thedirection of the aft portion of the human knee into the space thatnormally results between the tibia and femur when the same are angularlymoved toward each other. This is illustrated more clearly in theaforementioned figures of the drawing wherein the human flesh line isshown in dot-dash lines and is identified by the letters FL while thehuman knee is denoted by the letter K. As the inventive knee hinge 22 ismoved from its substantially straight standing or full recliningposition as shown in FIG. 2 toward its partially bent or sittingposition, as shown in FIG. 4, the engaging gear teeth 40 on thecooperating levers and links, cause the fulcrum housing 46 to bedisplaced linearly away from the theoretical pivot 64. During thismoveent, the upper lever 26 pivots at 30 relative to the upper housing32. Its engaging teeth 40, cooperating with the teeth on the upperbulbous ends of the link means 34 and 34a, cause such link means torotate about their pivots 36 and 38 respectively relative to the upperhousing 32 in which they are mounted.

At the same time, the lower lever 28, fixed for movement with theamputated tibia, rot-ates about its pivot 62 relative to the lowerhousing 60. Its gear teeth, cooperating with the engaging gear teeth onthe lower bulbous ends of the lower link means 48 and 50, cause the linkmeans to rotate about their pivots 56 and 58 respectively within thehousing 60. Inasmuch as the lower bulbous ends of the upper link means34 and 34a are fixedly pivoted in the fulcrum housing 46 arecooperatively engaged with the upper bulbous ends of the lower linkmeans 48 and 59 which are also fixedlypivoted in the same fulcrumhousing, the displacement of the upper and lower link means by theirupper and lower levers respectively, cause such link means to rotaterelative to each other about their pivots. Their pivoting rotationdisplaces the housing 46 linearly toward the aft portion of the humanknee joint into the angular space defined between the wearers femur andamputated tibia.

During this displacing movement, the upper bulbous portion of the linkmeans 34a is caused to move toward the adjacent concave surface of thelink means 34 while the lower bulbous surface of the link means 34 iscaused to move upwardly toward the adjacent concave face of the linkmeans 34a. A similar action and cooperation occurs with respect to thelower link means 48 and 50. Hence, the inner concave or arched surfacesof the adjacent link means 34, 34a, 48 and 50, serve to accommodate thebulbous end portions of the next adjacent link members when the hinge 22is moved toward its extreme bent position substantially as shown in FIG.7, enabling the hinge to perform its extreme movement.

In practice, the upper and lower housings 32 and 60 are closed along allsides thereof except for those portions that are required to be leftopen to permit the relative movement of the links and levers mountedtherein. The fulcrum housing 46, on the other hand, is fully enclosed onits aft side and open on its other three sides to permit the relativeengaged movement of the upper and lower link means about their pivotstherein. The closed sides of both the upper and lower housing and alsoof the fulcrum housing serve to completely enclose the working exposedportions of the gear teeth of the cooperating upper and lower links andlevers to prevent from gripping and tearing the clothes. The retractionof the fulcrum housing 46, linearly into the angular space formedbetween the femur and amputated tibia, eliminates and completelyobviates the possibility of unsightly bulges along the sides of thehuman knee joint.

In order to insure the proper angular movement of the inventive kneejoint 22 so that the angularly spaced upper and lower levers 26 and 28shall have a maximum and minimum limited angular movement about thetheoretical pivot 64, the engaging means or gear teeth 40 arepredeterminately arranged on the cooperating bulbous ends of the leversand links in number and size. By predeterminately selecting the size andnumber of cooperating teeth 40 and predeterminate-ly arranging the sameon the cooperating engaged ends of the levers and link means of thehinge 22, the maximum and minimum relative movement of such levers andlink means may be predetermined and limited. Thus it may be noted thatthe engaging means 40 defines a limiting structure which permitsrelative movement of the upper and lower levers to a predeterminedlimited maximum and minimum spacing. The engaging means thus insuresthat the relationship of the upper and lower levers relative to thetheoretical pivot 64 will be such as never to exceed the maximum andminimum angular positions that normal non-amputated femur and tibiaassume with respect to each other when actuated by a human knee.

In considering the instant invention, it is to be noted that the upperlever 26 of the hinges 22 disposed on opposite sides of the postureadapter 24, may be securely fixed with respect to a brace or rigid framestructure similar in nature to that disclosed in a co-pendingapplication, Serial No. 630,236, filed December 24, 1956, and now PatentNo. 2,915,760, while the'lower lever 28 is adapted to be fixed inrelation to the amputated tibia in any convenient manner, for example,by fixedly mounting the same on the boot structure 24 to be described.The boot structure 24 has an open top through which the amputated tibiais received. The lower portion of the boot 24 may be connected by someconvenient rigid supports to an artificial foot, not shown.

In the main, the boot structure 24 comprises a rigid metallic boot bodymember or leg skin 66 that is cut slightly higher along the lateralsides thereof than the front or aft portions. As is usual, the bootstructure 24 comprises a fabric or leather insert that seats in and isremovable from the metallic boot body or leg skin 66.

ince these minor details form no part of the invention, for purposes ofexplanation, the member 66 is referred to as the boot that is intendedto include the insert. The slightly higher sides are adapted toencompass portions of the sides of the human knee to provide lateralsupport therefor when the amputated tibia is firmly seated within theboot. This provides temporary additional support at the sides of theknee as the wearer rises to a standing position or bends his knee tosit. The front of the boot is formed slightly lower than the sides as toextend about the front portion of the human knee K and slightly beneaththe kneecap as not to interfere with the operation of the same. This maybe seen more clearly in the diagrammatic arrangement of the boot withrespect to the flesh line FL and knee K in FIGS. 2 to 7 inclusive.

In the instant invention, the aft portion 68 of the rigid body 66 is cutsubstantially lower than boot structures known heretofore, for a reasonto be described. In order that one may more clearly understand theoperation and function of the instant unique boot structure 24, it isimportant to recognize the boot structures presently in use bybelow-knee amputees, are rigid and immovable; that is to say, that theboot generally comprises no moving parts but rather includes a rigid,unyielding structure that peripherally encompasses the amputated tibia.Although the design of such boots has been predicated upon the beliefthat below-knee amputees must have adequate lateral and aft kneesupport, in the past this has been accomplished by providing higherlater-a1 sides 67, sufficient forward support in the area'definedimmediately beneath the human kneecap K, and a high rigid, unyieldingsupport about the aft portion of the knee.

However, in practice, the boot constructions thus described resulted ina cutting and rubbing at theaft portion of the knee when the wearerthereof performed various normal knee bending manipulations ormovements. Those skilled in the art will readily understand this whenthey realize that the boot construction 24 is generally fitted to befixedly mounted with respect to the femur when the wearer is in astanding position and his femur and tibia are in substantial verticalalignment. However, when the wearer of present rigid boot constructionsbends his knee to walk, sit or dangle his legs, the distance between theboot and the aft portion of the femur shortens as a result of theimperfect hinging action of the human knee. This shortening of thedistance between the top of the aft portion of the boot and the femur,results in bringing the aft portion of the rigid boot cutting upwardagainst the large flat muscles located above and at the aft side of theknee. Although this cutting effect is painful indeed, and the amputeeoften performs unusual and abnormal moving contortions to prevent it, itcannot be avoided in present rigid boot constructions. Moreover, thisupward cutting movement has the-effect of lifting or pulling the stumpout of the boot liner and out of full snug contact. therewith. Theelimination of this full contact prevents the amputee from using thefull area of his stump to control the boot thus making controlineffective.

The present invention recognizes this problem and has as its object toprovide a unique boot structure 24 that performs the function of aposture adapter, namely, to supply the support necessary at the aftportion of the knee, without the cutting elfect inherent in presentlyknown boot structures. This is accomplished in the instant invention byproviding a boot construction 24 comprising a rigid. boot 66 having atthe aft portion 68 thereof, a slide apparatus generally identified bythe numeral 70 that may be operated to vary the rear height of the bootin response to the relative movements of the femur and amputated tibia.The slide apparatus 70 is adapted to be actuated by a mechanism directlyrelated to the movement of the knee hinge 22, which in turn, is-directlycontrolled and corresponds to the relative angular movement of the femurand amputated tibia about the human knee K and of the knee joint 22about its theoretical pivot 64.

For a clearer illustration of the operation of the slide apparatus andits structural relation with the boot member 66, reference is made toFIGS. 1, 8 and 9. FIG. 8 is a partial view of the aft right side ofFIG. 1. Slide apparatus 70 comprises a slide means or structure 80, thatis freely movable relative to the aft portion 68 of the opening of theboot 66. Its free movement is guided by members 74 and 76 disposed onopposite sides thereof. Although only the one guide 74 is shown in fullin FIG. 1, it is to be recognized that the guides 74 and 76 aremirror-hand images of each other, and channel shaped. Each guide member74 and 76 is securely and fixedly mounted to its respective side of theboot 66 by a support 78 (only one of which is shown in FIG. 1) andpositioned slightly to the aft thereof to guide the slide member forfree sliding movement thereat.

The slide 80 may be a micarta plate that it substantially shorter inlength than the side guides 74 and 76. It has a free roller bearingengagement with both the body and side flanges of the side guides. Slideplate 80 is arcuately recessed at both of its lower end corners '82, toaccommodate therein roller means 84 that have their bearing surfacesarranged for rolling engagement with the body portions of the channelguides 74 and 76. In a similar manner the opposite top ends or cornersof the plate 80 are recessed at 86 to accommodate the roller means 88that are also arranged for rolling bearing engagement with the innersurfaces of the body portions of the channel guides.

The upper and lower roller bearing structures 84 and 88 thus preventundesired lateral or tilting movement of the plate 80 between theguides. Undesired forward and aft movement of the plate 80 relative tothe guides is eliminated by the provision of upper and lowerlongitudinally spaced roller bearing structures 90 and 92 positioned onopposite ends of the plate. The bearing surfaces of the rollingstructures 94) and 92 are arranged to engage with the inner surfaces ofthe inturned flanges of the guide members. This unique arrangement ofbearing engage ment insures against undesired or unwanted movement ofthe plate relative to its guides.

The lower set of bearing members 92 are mounted on pins 94 that aresecured into the ends of the-body 80 after the same are received insuitable recesses 6. The lower set of bearing means 84 are pivotly fixedin their recesses 82 by mounting brackets 98. Brackets 98 are somewhat Ushaped as seen in FIG. 9 to extend from one side of the plate 89 aboutthe underside thereof and along the other side. The brackets are fixedlysecured to the plate 80 at 190 to define the bearing mount arms 104.

The upper sets of bearings 88 and 90 are fixedly secured with respect tothe plate 80' by brackets 110. The brackets 110 are adapted to besecured to the forward and aft surfaces of the plate 80 by the securingmeans 112. The body engaging set of rollers 88 are pivotly mounted at114 to the upper brackets 110. An encompassing band 116 is adapted torotatably mount arposture adapted roller 118 to the plate 80. A pivotpin 120 extending through the roller a118, serves to mount the sideflange bearing member 99 at the opposite ends thereof.

From what has been described it will be seen that the posture adapterroller 118 is fixedly mounted by the brackets 110 to the plate 80 toform a part of the slide mechanism 70, thus it moves with the slidemechanism in response to the movements of the knee joint 22. The postureadapter roller 118 defines the top-most portion of the slide 70 forconstant engagement with the aft portion of the knee K, while the slidemechanism itself defines the aft portion of the opening of the boot 66.

, The slide mechanism 70 operatively serves to vary the height of theaft portion of the opening of the boot 66. It is operated in response tothe, movement of the hinge or end joint 22. For this reason it isadapted to be connected at its arm 108 by an inner actuator link 1 22 toa cam pivot or roller 124. An outer shorter arm or actuator link means126 is pivotly mounted at its upper end to the cam pivot or roller 124,and at its lower end it is pivotly mounted at 128 to the lower lever 28.The pivot or roller 124 is movable in a cam slot 130 of a cam memher 132that forms a part of a slide actuator mechanism.

The slide actuator mechanism may be seen more clearly in FIGS. 10 and llwherein it comprises the lower link means 59 and the cam actuator 132.The lower link means 50 is offset at 135, a distance equal to thethickness of the adjacent wall of the lower housing 60,0ver which it isadapted to slide and move in a manner depicted more clearly in FIGS. 2to 7 inclusive. To provide for the smooth relative sliding movement ofthe cam actuator 130 over the adjacent surface of the lower housing 69,the cam actuator is provided with a nose portion 137 that is continuallyin overlapping relationship with the adjacent surface of the housing 60.The smooth relative sliding movement of the nose 137 over the lowerhousing 60 insures against the gripping of clothing and obviates thepossibility that adjacent portions of garments covering the same willnot be caught therehetween, thus eliminating the possibility of tearingof clothing.

It is noted that the outer and inner link means 126 and 122 are operableon opposite sides of the cam actuator 132; that is to say, the outerlink 126 moves over the outer surface of the cam actuator, while theinner link moves laterally against the inner adjacent offset surface ofthe cam actuator.

The actuating mechanism including the cam actuator 132 is operatedduring the operation of the knee joint 22 in response to the movement oflink 50 of which it forms a part. As the cam actuator is displaced fromits position shown in FIG. 2 towards its position as shown in FIG. 7,during the bending of the knee K from its substantially aligned positionas shown in FIG. 2, to its extreme bent position as shown in FIG. '7 thecam pivot or roller 124 is caused to move relative to the cam opening130. The cam opening or guide 130 is predeterminately formed or shapedto selectively permit the raising or lowering of the slide mechanism 79.When the mechanism 70 is operated its attendant posture adapter roller118 is moved also to vary the height of the aft of the opening of theboot 66 to remain in constant supporting engagement with a predeterminedaft portion of the Wearers knee K. This is illustrated in the figures ofthe drawing wherein the posture adapter roller 11?; is caused to move upor down relative to the rear of the boot 66. As such it forms a constantposture support for the aft portion of the knee K at a height thatprovides the wearer with the greatest feeling of support throughout alldegrees of bending movement of the knee.

The amputee may be said to be in the standing or in the completereclining position when the femur and tibia are substantially inalignment and the included angle therebetween is at a maximum as shownin PEG. 2. in this position'the cam roller 124 is at the lowermost endof its travel in the cam slot or guide and the actuator link means 122and 126 interconnect the knee joint 22 with the slide mechanism 70. Asthe knee K is slightly bent from its position in FIG. 2 to its positionas shown in FIG. 4, reducing the included angle between the amputatedtibia and femur, hinge 22 is actuated to retract the fulcrum housing 46linearly rearward away from the theoretical pivot 64.

During this movement, the link 50 and its integral cam actuator 132 isdisplaced. The links 122 and 126 of the actuator mechanism, being fixedat their ends 123 and 128 respectively, permit the cam slot to moverelative to the joining cam roller 124. As noted previously, as theangle between the amputated tibia and femur decreases the boot 66 isdisplaced upwards along the knee K toward the aft portion thereof andthe aft portion of the femur, cutting into the muscles at the back ofthe knee. This cutting elfect normally occurs when the amputated tibiaand femur are in their relative positions as shown in FIG. 5. Therefore,unless some means is provided whereby the aft portion of the opening ofthe boot in which the amputated tibia is received is variable, the samewill dig and cut progressively deeper into'the muscles as the tibia andfemur are bent further and progressively toward each other.

For this reason the guide 130 is predeterminedly designed and shaped toactuate the slide mechanism 70' to vary the aft height of the boot 66,only after knee K is bent into the position in FIG. 5 and progressivelytherebeyond. To facilitate this operation the cam Opening 130 isinitially predeterminedly curved and terminates in a displacing linearcam portion 134 that begins abruptly at 136. Although the fulcrumhousing 46 is displaced linearly throughout the progressive relativebending movement of the amputated tibia and femur, the curved camsurface is predeterminedly shaped such that its travel relative to thecam follower 124 prevents corresponding movement of the slide mechanism70. However, as link 50 is continually lowered by the progressive andcontinued bending of the knee K, the follower 124 is caused to pass overthe critical point 136 and into the confines of the displacing camportion 134. Thereafter further continued progressive bending movementof the knee K operates the parts of the knee joint 22 such that the link50 and its cam actuator 132 are moved relative to the follower 124 toposition the same linearly within and along the displacing portion 134.The predetermined linear shape of camp portion 134 serves to operate theactuator link means 126 and 122 in a straight line motion to lower theslide mechanism 70 relative to the remainder 0f the boot 66, a distancecorresponding to the upward displacing movement of the boot relative tothe aft portion of the knee K.

Accordingly the posture adapter roller 118 remains in constant physicalengagement with a predetermined aft portion of the wearers knee Kthroughout all movements of the boot 66 relative to the femur, knee Kand amputated tibia. By varying the height of the aft portion of theopening of the boot 66, the boot is permitted to move relative to theamputated tibia received therein and upward towards the aft portion ofthe femur as the knee K is bent to the position shown in FIG. andtherebeyond. The ability to vary the height of the aft portion of theopening during such bending movements, and at the same time provide theamputee with the necessary support at the aft part of the knee K, is amajor advance in the art. It completely eliminates the cutting that isnow in evidence in rigid boot constructions, yet at the same timeprovides the proper support where the same is needed.

Although the description and figures of the drawings disclose the slidemechanism to be operated at both of its arms 102, one of these arms, maybe eliminated. The operation of the mechanism 70 at the sole remainingarm 102 by the hinge 22 will suffice since the same does move freely andsmoothly between its guides 74 and 76.

Referring to FIGS. 1, 8 and 9, there is shown a fabric lining orcovering 138 that is a continuation of the fabric lining of the boot 66and is adapted to comfortably fit about the amputated tibia. In theinstant invention the lining strip 138 is passed over the postureadapter roller 118 and is lightly spring loaded by a convenientlylocated spring 140 (FIG. 9) to keep the strip and its fabric liner tautat all times during the movements of the slide mechanism 70.

While there have been shown and described and pointed out thefundamental novel features of the invention as applied to a preferredembodiment thereof, it will be understood that various omissions andsubstitutions and changes in the form and details of the deviceillustrated and in its operation may be made by those skilled in theart, without departing from the spirit of the invention. It is theintention, therefore, to be limited only as indi cated by the scope ofthe claims appended thereto.

I claim:

1. An anatomical knee comprising relatively displaceable upper and lowerlevers, movable link means between said levers, means on said link meansand levers having frictional engagement to interconnect the same forrelative displacement and to move said link means in response to therelative displacement of said levers, and means on which said link meansare pivoted to retain said link means in said frictional engagement,said last named means being displaceable in response to the relativedisplacement of said levers and the movement of said links.

2. An anatomical knee having a theoretical pivot comprising an upperlever movable about said pivot, a lower lever movable about said pivot,means between said levers movable toward and away from said pivot, andupper and lower link means pivoted on said means, said upper and lowerlink means each having friction means connected with said upper andlower levers respectively and with each other to move said means betweensaid levers in response to the movement of said levers about said pivot.

3. An anatomical knee comprising angularly displaceable upper and lowerlevers, means displaceable in response to the angular displacement ofsaid levers, upper and lower link means, means movably engaging saidupper and lower link means with said upper and lower levers respectivelyfor movement thereby in response to the angular displacement of saidlevers, and means movably engaging said link means with each other andpivoted on said fulcrum means to displace the same.

4. An anatomical knee having a theoretical knee pivot comprising anupper lever housing, an upper lever pivoted in said housing, upper linkmeans pivoted in said upper housing and engaging said upper lever forpivoted relative movement, a lower lever housing, a lower lever pivotedin said lower housing, lower link means pivoted in said lower housingand engaging said lower lever for pivoted relative movement, a fulcrumhousing, said upper and lower link means being pivotedly engaged forrela- 10 tive movement in said fulcrum housing, and engaging means onsaid engaged lever and link means to limit the relative movementtherebetween.

5. A prosthesis for below-knee amputees comprising an artificial kneejoint including upper and lower levers fixed with respect to the wearersfemur and amputated tibia respectively for angular relative movementtherewith, fulcrum means, upper and lower link means engaged for limitedrelative movement with said upper and lower levers respectively andpivotally engaged with each other in said fulcrum means for limitedrelative movement in response to the relative angular movement of saidlevers to displace said fulcrum means, a boot in which the amputatedtibia is received, means movable on said boot to vary the rear heightthereof, and means to move said movable means in response topredetermined relative angular movements of said levers.

6. A prosthesis as in claim 5, said boot being fixed for angularmovement with said amputated tibia, and said lower lever being fixed tosaid boot for movement therewith.

7. The combination of an anatomical knee and posture adapter forbelow-knee amputees comprising a boot to receive the amputated tibia, aknee joint, said knee joint having an upper lever fixed with respect tothe femur, a lower lever fixed with respect to said boot, said leversbeing movable to permit relative angular movement between the femur andsaid boot, link means interconnecting said levers for said relativemovement, means movable on said boot to vary the rear height of saidboot in response to the relative movement of said levers, and meansinterconnecting said movable means with said knee joint.

8. The combination of a knee joint and posture adapter for below-kneeamputees, said knee joint being movable and comprising levers movable inaccordance with the relative movements of the femur and amputed tibia, aboot to receive the amputated tibia, link means interconnecting saidlevers and movable in response to the movement of the same, means onsaid boot constantly engaging the aft portion of the knee and movable tovary the rear height of said boot, and means connecting said movablemeans on said boot with said knee joint to move the same in response tothe movement of said joint.

9. A prosthesis for below-knee amputees comprising an artificial movableknee joint having lever means fixed with respect to the femur andamputated tibia for corresponding movements therewith, a boot in whichthe amputated tibia is received, means on the aft portion of said bootoperably connected to said knee joint to move in response to themovements of said joint and to remain in constant engagement with apredetermined aft portion of the wearers knee.

10. A prosthesis for below-knee amputees comprising a boot adapted toreceive the amputated tibia for movement therewith and having an aftportion thereof movable to constantly engage a predetermined aft portionof the wearers knee, a knee hinge having means movable with said bootand including means to move said aft portion of said boot.

11. A prosthesis for below-knee amputees comprising a boot adapted toreceive the amputated tibia for movement therewith, means on said bootslidable along a portion thereof to assume a fixed position with respectto the wearers knee, a knee hinge including means fixed for movementwith respect to said boot and the wearers femur, and meansinterconnecting said knee hinge with said slidable means to slide thesame in response to the relative movement of said tibia and femur.

1'2. A prosthesis for below-knee amputees comprising a boot adapted toreceive the amputed tibia for movement therewith, said boot having anaft portion operable to 'vary the aft height thereof in accordance withthe relative movements of the wearers femur and tibia, a knee hingehaving upper and lower levers fixed for rela- 1 I tive angular movementscorresponding to the relative angular movements of said femur and tibiarespectively, and means on said knee hinge interconnected with said aftportion to operate the same.

13. A prosthesis for below-knee amputees comprising a knee hinge havingupper and lower levers fixed for relative angular movement with respectto the wearers femur and amputated tibia respectively, actuator meansmovable in response to the relative angular movements of said upper andlower levers, a boot in which the amputated tibia is received, means onsaid boot operable to vary the aft height thereof in accordance with therelative angular movements of said femur and tibia, and means connectingsaid lower lever and said actuating means with said movable means tooperate said movable means to vary the aft height of said boot inaccordance with the relative angular movements of said femur and tibia.

14. A prosthesis for below-knee amputees comprising a boot, said boothaving an opening at the top thereof through which the amputated tibiais adapted to extend for receipt in said boot, a slide defining the aftportion of said opening of said boot and being freely movable along thelength of said boot, and means bearingly mounting said slide for saidfree movement.

15. A prosthesis as in claim 14, arm means on said slide extendinglaterally from the sides of said boot and adapted tornove the slidealong the length of said boot to vary the height of the aft portion ofsaid opening.

-16. A prosthesis for below-knee amputees comprising a boot having anopening at the top portion thereof for the receipt of the amputed tibiatherein, a slide defining the aft portion of said opening and movablealong the length of said boot to vary the height of said/aft portion ofsaid opening, arm means on said slide extending laterallyfrom the sidesof said boot to move said slide freely along the length thereof, a kneehinge including upper and lower levers fixed for relativeangular'movement with the wearers femur and amputated tibia respectivelyand actuator means, said actuator means being movable in response to therelative angular movements of said upper References Cited in the tile ofthis patent UNITED STATES PATENTS 47,353 Burr I. Apr. 18, 1865 2,590,782Mayack Mar. 25, 1952 FOREIGN PATENTS 79,821 Austria Jan. 26, 1920

